w. H. ADAMS: LATE MEDICAL CONSEQUENCES OF EXPOSURE TO RADIOACTIVE THYROID DISEASE vs. RADIATION DOSE 100 -induced cancer. en equated with cancer ortality. Since cancer ment iber of cases PERCENT OF POPULATION IN EACH DOSE CATEGORY 90 + 80 70 1 t T T 7 (7) BENIGN NODULES SJ HYPOTHYROIDISM | THYROID CANCERS 7 60 F 4 50 4 SSSHSSSSHHSs VLLLLLLLLLLLL fferent types of cancer 40 30 1 20 » ea Ler LAA 10 1-250 051:-500 7 4 _ 4 501 “1000 1001-2 -2000 2001 -3000 3001-4000 4001--5000 REM a Figure 6. Thyroid-absorbed radiation dose and subsequent developmentof benign thyroid nodules, thyroid carcinomas, and hypofunction. population, both benign nodules and thyroid hypofunction display a similar correlation with urring cancer mortality,it g the radiation-exposed ancer tisk. On the other lisease, principally of the sions have been of great radiation (Figure 6), and in contrast to thyroid cancer, adenomatous nodules have been very common (Table 6). Adenomatous nodulesare rarely of clinical significance, because they do not evolve into cancers. Surgery is necessary only to exclude the latter diagnosis. Nevertheless, the clinical evaluation required to establish a diagnosis is associated with its own morbidity. Prominent in this morbidity is thyroid surgery itself, a procedure that requires general anesthesia and results in a cosmetic defect and the unavoidable removal of some normalthyroid tissue. Thyroid Hypofunction, Radiation-Induced up have had surgery for oid nodules found in the ad adenomatous nodules. »mas, are benign, and are c lesions. In the exposed Overt hypothyroidism was diagnosed in two Rongelap boys who wereinfants at the time of exposure (11). In addition, subclinical hypothyroidism unrelated to thyroid surgery was confirmed in twelve other Rongelap persons (22). In 1987, a Utirik man was diagnosed as biochemically hypothyroid. He was twoyears of age at the time of exposure, and heis the first exposed person from Utirik to have this diagnosis. 287